12V Guru – AGM Battery Storage

12V Guru – AGM Battery Storage

We regularly are asked by our readers as to what is the best practise and recommended storage for batteries in caravans, so this month we’ve decided we’re going to put together our top tips for not only the safe AGM battery storage but good maintenance of your batteries.

There are two main types of battery chemistries that are being used in RV’s across Australia. The first is the tried and tested lead-acid battery which everybody would be familiar with and the second is the cutting-edge technology that lithium brings to our adventures. Ensuring that you have properly secured and maintained your batteries will ensure many years of great use and also protect probably the second most expensive replacement item in the caravan after a set of 4 new tyres.

This article deals with the storage of Lead Acid batteries. As most are aware, there are multiple versions of the traditional lead-acid battery which include Gel, Flooded, AGM etc, however, from a storage perspective they all have similar requirements. The most common battery used in the RV market is the AGM as it requires less maintenance and less chance of venting noxious and dangerous gases. AGM does absorb the majority of the gases created internally in an AGM battery however if there is an excessive build-up due to incorrect charging. These batteries will all “vent” when there is a build-up of gas pressure inside and whilst to the naked eye it may not be obvious, there will be a small vent(s) built into the top of the plastic case (or sometimes the top of the side wall) that allows for excess gas to pass through and reduce the internal pressure of the battery.  Without this vent, the battery could swell within its case and cause even more damage.  This can be seen sometimes when a 2V cell within the battery has been damaged and it continues to overcharge, and the gases can’t vent adequately to protect the battery integrity.

  1. Ensure the battery is secured – regularly checking the mechanism used to secure the battery in your caravan will ensure it does not become loose and risk damage to itself or other electrical devices located nearby. AGM batteries contain lead plates internally and excessive vibration or impact will most likely cause damage leading to some of the above issues
  2. Vent to outside – Properly considered installations should have a level of venting to the outside environment. To prevent a build-up of these gases in a confined space it is advisable to ensure a suitable vent between the battery compartment and the exterior of your caravan.  It does not have to be large or impact the inside temperature but should at least allow for a movement of any built-up gas (if any) and the outside environment
  3. Battery Compartment is for Battery only – check your battery compartment regularly to ensure that only batteries and related cabling etc are stored within. We all know that space is precious inside a caravan which is why too often we have seen batteries being stored with anything from excess pillows to acting as the spare drinks compartment.  Smart caravan manufacturers will have ensured that the battery storage compartment is not too large and therefore tempting to use as a location for those extras.
  4. External storage – if the design of your caravan allows or is optioned accordingly, we would highly recommend storage of all AGM batteries outside of the living area of your caravan. Several manufacturers have now created storage fixtures for lead-acid batteries under the floor of the caravan and are attached to the chassis frame.
  5. Battery Charge Level – we recommend that you do not keep your battery charger or Power Management System permanently connected to your battery whilst in storage.  When you first put your caravan into storage for a few months charge your battery the day before and then turn off the AC power.  AGM batteries prefer to be “exercised” and allow for the voltage to drop naturally over time and then recharged.  Give your battery a “top-up” charge every 2-3 months.

Similar to how you would look out for the tyres on your caravan to ensure you maximised the investment and ensured the safety of your caravan, maintaining your battery properly will ensure not only you and your family’s safety but the longevity of such a critical component to enjoying your next trip.

Safe travels,

12V Guru

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